This is something I don't get. They attack all humans they see and they actually keep people as ransom for caps. Why do they need money? It's not like they're spending them.

Money can be exhanged for goods and services!

https://www.youtube.com/watch?v=dgct3Jn8pFA

Well since we are on the topic. Bottlecaps is the current currency. Why do I find Bottlecaps when looting prewar people/items?

Not to mention finding pipe weapons in prewar safes.

Because just like with Princess Peach, the settler is having an affair, and just using being kidnapped as an excuse to get out of the house and get some spending money for the date. That's why the same person gets kidnapped 20 times a day.

Well, if you listen to a holotape made by a super mutant named hammer you will learn that they trade between clans/ groups/ whatever they group into. He is telling a super mutant that he found a good place to live and raid from. Offering guns in trade to another leader in exchange for him sending more mutants to the former's camp so they can raid more.

They need the caps for their weekly poker game.

To buy treats for the humans.

Heh, you got there first. I was gonna say gambling.

That makes sense. Thank you.

Personally, I think they send the ransom note so they can get a human to come and deliver the ransom. Then they can eat the hostage and the guy bringing the ransom money as well.

That said, I've never tried ransoming a mutie kidnap victim, so I've no idea if it works or not.